Giant shutter?

[cosmicexplosion]

interesting cgrab, thanks.
i just looked on ebay de, and yes there is a 13x18 with shutter, the aktar is f2.5, so i am not sure how big the shutter opening is in mm, any chance you could find out, my german is a bit rusty, thou i could use google translator?

mr feeble, what is a gravity drop shutter? is it just something you let drop,?

[Lachlan 717]

Gravity drop shutters are long strips of card/board/plastic/metal that have a given spacing in the middle. So, you start with the strip up high (where the bottom, solid section acts as a closed shutter), and drop it.

The gap acts somewhat like a curtain shutter, where the length of the gap determines the exposure time (longer gap=longer exposure).

The solid top section then also acts as a closed shutter.

Better get accustomed to working out fractions of 9m per second per second...

[numnutz]

Gravity drop shutters are long strips of card/board/plastic/metal that have a given spacing in the middle...

like this one...

http://www.youtube.com/watch?v=0F7LZiQHsqo

nn

[Old-N-Feeble]

Here's another link: Guillotine Shutter Design

[polyglot]

Have you thought about using a slab of LCD? They don't have a huge Dmax but it's probably enough to get you a fastish (1/100) shutter if you cover it mechanically with something slower.

Edit: supplier
Edit II: I emailed for a 150x150mm price. If they're affordable (~$100), I could feasibly build a batch of electronic shutters for people here to buy.

[TheDeardorffGuy]

Have you thought about using a slab of LCD? They don't have a huge Dmax but it's probably enough to get you a fastish (1/100) shutter if you cover it mechanically with something slower.

Edit: supplier

Last year in Chicago I saw a photographer shooting a Deardorff V11. He had a 7x7 board with huge Nikkor APO on the front. there were wires coming out of the board to a controler. I asked him if it was a Packard Shutter. Nope! He smiled and removed the board and showed me a totaly opaque LCD glass mounted to the rear cell. The LCD glass was capable of on off on cycle of nearly a thousanth.His controler was adjustable from 10 minutes to 1/1000. I have not looked up LCD glass. Sorry. It looked very clear when on.

[Jody_S]

As an occasional DIY-er/builder, probably the easiest system to build from scratch (well, 2nd to the 'gravity shutter' setup) is a rotary system. Basically, you need a spring/elastic/electric system of rotating a large wheel with a slit in it, and you simply make as many wheels as you need speeds by varying the width of the slit. If you're able to make a multi-speed rotation device, that would obviously reduce the number of wheels you need to carry around. 2 wheels in a sandwich, making a variable slit? None of this is hard to make with basic hand tools and some sheet metal.

[polyglot]

They replied that tooling setup for 150x150 shutters would be about $2500, though they're already setup to produce 100x100 pi cells for $100 each, plus a bit extra for compensating film.

They're not big enough for craziness like a 300/2.5, but you could happily shoot 200/2.5 or 360/4 through such a shutter. By the time you add a controller and mechanicals, you'd be looking at probably $300-400 per shutter, which I think is well reasonable for such a huge size and the ability to do 1/500 up to hours, not to mention intervalometer behaviour. If you were very DIY-capable, you could do a basic materials-only for about $150 I think.

Would people here be willing to buy 100mm shutters for about $400?

[buggz]

I would, though, complete specs would be needed.

Would people here be willing to buy 100mm shutters for about $400?

[cosmicexplosion]

i think i might use a hat!